In the event of an over-speed, the valves that activate to shut down the engine are which?

• A. overspeed valve and drain valve
• B. fuel flow valve and oil pressure valve
• C. temperature valve and relief valve
• D. start valve and purge valve

Answer: (A)

When an engine reaches an overspeed condition, the safety system kicks in to stop the engine quickly and prevent damage. The two valves involved are a dedicated overspeed valve, which immediately cuts off the fuel supply to halt combustion, and a drain valve, which allows any remaining fuel in the line to be drained so there’s nothing left to ignite. This combo ensures a rapid, clean shutdown.

The other options don’t fit the overspeed shutdown mechanism: a fuel flow valve is part of normal fuel metering rather than a protective trigger; oil pressure and temperature valves handle lubrication and thermal limits, not rapid shutdown from overspeed; start and purge valves are used for starting and clearing the system, not for stopping due to overspeed.